Fluidelastic Instability in Tube Arrays Subject to Two-Phase Cross Flow: A Porous Medium Approach
Bibliographic record
Abstract
In nuclear power plants, heat exchangers undergo important flow induced vibrations, fluidelastic instability (FEI) being the most damaging one. Direct numerical simulations of such a phenomenon is currently an impossible task because of the considerable number of tubes and the two-phase nature of the flow. The novelty of the present approach is to use a porous medium to model the tube bundle and the surrounding flow. The Navier-Stokes equations are averaged on a control volume and the tubes materialized by a porosity field and source terms that model the interactions between the fluid and the solid. New sets of fully coupled equations were developed and solved with a finite element solver using high order time integration schemes. The unsteady porous medium approach already developed for single-phase flow is extended to the Euler-Euler formulation to describe the two-phase mixture. Validation and calibration of the parameters are achieved by comparing the critical flow rate and the forces acting on the tubes with results from direct numerical simulations and experimental data for single-phase flows.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".